import {
  Color,
  DefaultLoadingManager,
  FileLoader,
  FrontSide,
  Loader,
  LoaderUtils,
  MeshPhongMaterial,
  RepeatWrapping,
  TextureLoader,
  Vector2
} from "../../build/three.module.js";

/**
 * Loads a Wavefront .mtl file specifying materials
 */

var MTLLoader = function (manager) {

  Loader.call(this, manager);

};

MTLLoader.prototype = Object.assign(Object.create(Loader.prototype), {

  constructor: MTLLoader,

  /**
   * Loads and parses a MTL asset from a URL.
   *
   * @param {String} url - URL to the MTL file.
   * @param {Function} [onLoad] - Callback invoked with the loaded object.
   * @param {Function} [onProgress] - Callback for download progress.
   * @param {Function} [onError] - Callback for download errors.
   *
   * @see setPath setResourcePath
   *
   * @note In order for relative texture references to resolve correctly
   * you must call setResourcePath() explicitly prior to load.
   */
  load: function (url, onLoad, onProgress, onError) {

    var scope = this;

    var path = (this.path === '') ? LoaderUtils.extractUrlBase(url) : this.path;

    var loader = new FileLoader(this.manager);
    loader.setPath(this.path);
    loader.setRequestHeader(this.requestHeader);
    loader.setWithCredentials(this.withCredentials);
    loader.load(url, function (text) {

      try {

        onLoad(scope.parse(text, path));

      } catch (e) {

        if (onError) {

          onError(e);

        } else {

          console.error(e);

        }

        scope.manager.itemError(url);

      }

    }, onProgress, onError);

  },

  setMaterialOptions: function (value) {

    this.materialOptions = value;
    return this;

  },

  /**
   * Parses a MTL file.
   *
   * @param {String} text - Content of MTL file
   * @return {MTLLoader.MaterialCreator}
   *
   * @see setPath setResourcePath
   *
   * @note In order for relative texture references to resolve correctly
   * you must call setResourcePath() explicitly prior to parse.
   */
  parse: function (text, path) {

    var lines = text.split('\n');
    var info = {};
    var delimiter_pattern = /\s+/;
    var materialsInfo = {};

    for (var i = 0; i < lines.length; i++) {

      var line = lines[i];
      line = line.trim();

      if (line.length === 0 || line.charAt(0) === '#') {

        // Blank line or comment ignore
        continue;

      }

      var pos = line.indexOf(' ');

      var key = (pos >= 0) ? line.substring(0, pos) : line;
      key = key.toLowerCase();

      var value = (pos >= 0) ? line.substring(pos + 1) : '';
      value = value.trim();

      if (key === 'newmtl') {

        // New material

        info = {name: value};
        materialsInfo[value] = info;

      } else {

        if (key === 'ka' || key === 'kd' || key === 'ks' || key === 'ke') {

          var ss = value.split(delimiter_pattern, 3);
          info[key] = [parseFloat(ss[0]), parseFloat(ss[1]), parseFloat(ss[2])];

        } else {

          info[key] = value;

        }

      }

    }

    var materialCreator = new MTLLoader.MaterialCreator(this.resourcePath || path, this.materialOptions);
    materialCreator.setCrossOrigin(this.crossOrigin);
    materialCreator.setManager(this.manager);
    materialCreator.setMaterials(materialsInfo);
    return materialCreator;

  }

});

/**
 * Create a new MTLLoader.MaterialCreator
 * @param baseUrl - Url relative to which textures are loaded
 * @param options - Set of options on how to construct the materials
 *                  side: Which side to apply the material
 *                        FrontSide (default), THREE.BackSide, THREE.DoubleSide
 *                  wrap: What type of wrapping to apply for textures
 *                        RepeatWrapping (default), THREE.ClampToEdgeWrapping, THREE.MirroredRepeatWrapping
 *                  normalizeRGB: RGBs need to be normalized to 0-1 from 0-255
 *                                Default: false, assumed to be already normalized
 *                  ignoreZeroRGBs: Ignore values of RGBs (Ka,Kd,Ks) that are all 0's
 *                                  Default: false
 * @constructor
 */

MTLLoader.MaterialCreator = function (baseUrl, options) {

  this.baseUrl = baseUrl || '';
  this.options = options;
  this.materialsInfo = {};
  this.materials = {};
  this.materialsArray = [];
  this.nameLookup = {};

  this.side = (this.options && this.options.side) ? this.options.side : FrontSide;
  this.wrap = (this.options && this.options.wrap) ? this.options.wrap : RepeatWrapping;

};

MTLLoader.MaterialCreator.prototype = {

  constructor: MTLLoader.MaterialCreator,

  crossOrigin: 'anonymous',

  setCrossOrigin: function (value) {

    this.crossOrigin = value;
    return this;

  },

  setManager: function (value) {

    this.manager = value;

  },

  setMaterials: function (materialsInfo) {

    this.materialsInfo = this.convert(materialsInfo);
    this.materials = {};
    this.materialsArray = [];
    this.nameLookup = {};

  },

  convert: function (materialsInfo) {

    if (!this.options) return materialsInfo;

    var converted = {};

    for (var mn in materialsInfo) {

      // Convert materials info into normalized form based on options

      var mat = materialsInfo[mn];

      var covmat = {};

      converted[mn] = covmat;

      for (var prop in mat) {

        var save = true;
        var value = mat[prop];
        var lprop = prop.toLowerCase();

        switch (lprop) {

          case 'kd':
          case 'ka':
          case 'ks':

            // Diffuse color (color under white light) using RGB values

            if (this.options && this.options.normalizeRGB) {

              value = [value[0] / 255, value[1] / 255, value[2] / 255];

            }

            if (this.options && this.options.ignoreZeroRGBs) {

              if (value[0] === 0 && value[1] === 0 && value[2] === 0) {

                // ignore

                save = false;

              }

            }

            break;

          default:

            break;

        }

        if (save) {

          covmat[lprop] = value;

        }

      }

    }

    return converted;

  },

  preload: function () {

    for (var mn in this.materialsInfo) {

      this.create(mn);

    }

  },

  getIndex: function (materialName) {

    return this.nameLookup[materialName];

  },

  getAsArray: function () {

    var index = 0;

    for (var mn in this.materialsInfo) {

      this.materialsArray[index] = this.create(mn);
      this.nameLookup[mn] = index;
      index++;

    }

    return this.materialsArray;

  },

  create: function (materialName) {

    if (this.materials[materialName] === undefined) {

      this.createMaterial_(materialName);

    }

    return this.materials[materialName];

  },

  createMaterial_: function (materialName) {

    // Create material

    var scope = this;
    var mat = this.materialsInfo[materialName];
    var params = {

      name: materialName,
      side: this.side

    };

    function resolveURL(baseUrl, url) {

      if (typeof url !== 'string' || url === '')
        return '';

      // Absolute URL
      if (/^https?:\/\//i.test(url)) return url;

      return baseUrl + url;

    }

    function setMapForType(mapType, value) {

      if (params[mapType]) return; // Keep the first encountered texture

      var texParams = scope.getTextureParams(value, params);
      var map = scope.loadTexture(resolveURL(scope.baseUrl, texParams.url));

      map.repeat.copy(texParams.scale);
      map.offset.copy(texParams.offset);

      map.wrapS = scope.wrap;
      map.wrapT = scope.wrap;

      params[mapType] = map;

    }

    for (var prop in mat) {

      var value = mat[prop];
      var n;

      if (value === '') continue;

      switch (prop.toLowerCase()) {

        // Ns is material specular exponent

        case 'kd':

          // Diffuse color (color under white light) using RGB values

          params.color = new Color().fromArray(value);

          break;

        case 'ks':

          // Specular color (color when light is reflected from shiny surface) using RGB values
          params.specular = new Color().fromArray(value);

          break;

        case 'ke':

          // Emissive using RGB values
          params.emissive = new Color().fromArray(value);

          break;

        case 'map_kd':

          // Diffuse texture map

          setMapForType("map", value);

          break;

        case 'map_ks':

          // Specular map

          setMapForType("specularMap", value);

          break;

        case 'map_ke':

          // Emissive map

          setMapForType("emissiveMap", value);

          break;

        case 'norm':

          setMapForType("normalMap", value);

          break;

        case 'map_bump':
        case 'bump':

          // Bump texture map

          setMapForType("bumpMap", value);

          break;

        case 'map_d':

          // Alpha map

          setMapForType("alphaMap", value);
          params.transparent = true;

          break;

        case 'ns':

          // The specular exponent (defines the focus of the specular highlight)
          // A high exponent results in a tight, concentrated highlight. Ns values normally range from 0 to 1000.

          params.shininess = parseFloat(value);

          break;

        case 'd':
          n = parseFloat(value);

          if (n < 1) {

            params.opacity = n;
            params.transparent = true;

          }

          break;

        case 'tr':
          n = parseFloat(value);

          if (this.options && this.options.invertTrProperty) n = 1 - n;

          if (n > 0) {

            params.opacity = 1 - n;
            params.transparent = true;

          }

          break;

        default:
          break;

      }

    }

    this.materials[materialName] = new MeshPhongMaterial(params);
    return this.materials[materialName];

  },

  getTextureParams: function (value, matParams) {

    var texParams = {

      scale: new Vector2(1, 1),
      offset: new Vector2(0, 0)

    };

    var items = value.split(/\s+/);
    var pos;

    pos = items.indexOf('-bm');

    if (pos >= 0) {

      matParams.bumpScale = parseFloat(items[pos + 1]);
      items.splice(pos, 2);

    }

    pos = items.indexOf('-s');

    if (pos >= 0) {

      texParams.scale.set(parseFloat(items[pos + 1]), parseFloat(items[pos + 2]));
      items.splice(pos, 4); // we expect 3 parameters here!

    }

    pos = items.indexOf('-o');

    if (pos >= 0) {

      texParams.offset.set(parseFloat(items[pos + 1]), parseFloat(items[pos + 2]));
      items.splice(pos, 4); // we expect 3 parameters here!

    }

    texParams.url = items.join(' ').trim();
    return texParams;

  },

  loadTexture: function (url, mapping, onLoad, onProgress, onError) {

    var texture;
    var manager = (this.manager !== undefined) ? this.manager : DefaultLoadingManager;
    var loader = manager.getHandler(url);

    if (loader === null) {

      loader = new TextureLoader(manager);

    }

    if (loader.setCrossOrigin) loader.setCrossOrigin(this.crossOrigin);
    texture = loader.load(url, onLoad, onProgress, onError);

    if (mapping !== undefined) texture.mapping = mapping;

    return texture;

  }

};

export {MTLLoader};
